A detailed finite element model of a mid-sized male for the investigation of traffic pedestrian accidents

Author(s):  
Daniel Grindle ◽  
Wansoo Pak ◽  
Berkan Guleyupoglu ◽  
Bharath Koya ◽  
F Scott Gayzik ◽  
...  

The pedestrian is one of the most vulnerable road users and comprises approximately 23% of the road crash-related fatalities in the world. To protect pedestrians during Car-to-Pedestrian Collisions (CPC), subsystem impact tests are used in regulations. These tests provide insight but cannot characterize the complex vehicle-pedestrian interaction. The main purpose of this study was to develop and validate a detailed pedestrian Finite Element (FE) model corresponding to a 50th percentile male to predict CPC induced injuries. The model geometry was reconstructed using a multi-modality protocol from medical images and exterior scan data corresponding to a mid-sized male volunteer. To investigate injury response, this model included internal organs, muscles and vessels. The lower extremity, shoulder and upper body of the model were validated against Post Mortem Human Surrogate (PMHS) test data in valgus bending, and lateral/anterior-lateral blunt impacts, respectively. The whole-body pedestrian model was validated in CPC simulations using a mid-sized sedan and simplified generic vehicles bucks and previously unpublished PMHS coronal knee angle data. In the component validations, the responses of the FE model were mostly within PMHS test corridors and in whole body validations the kinematic and injury responses predicted by the model showed similar trends to PMHS test data. Overall, the detailed model showed higher biofidelity, especially in the upper body regions, compared to a previously reported simplified pedestrian model, which recommends using it in future pedestrian automotive safety research.

Author(s):  
Costin D. Untaroiu ◽  
Jacob B. Putnam ◽  
Jeremy Schap ◽  
Matt L. Davis ◽  
F. Scott Gayzik

Pedestrians represent one of the most vulnerable road users and comprise nearly 22% of the road crash related fatalities in the world. Therefore, protection of pedestrians in the car-to-pedestrian collisions (CPC) has recently generated increased attention with regulations which involve three subsystem tests for adult pedestrian protection (leg, thigh and head impact tests). The development of a finite element (FE) pedestrian model could be a better alternative that characterizes the whole-body response of vehicle–pedestrian interactions and assesses the pedestrian injuries. The main goal of this study was to develop and to preliminarily validate a FE model corresponding to a 50th male pedestrian in standing posture. The FE model mesh and defined material properties are based on the Global Human Body Modeling (GHBMC) 50th percentile male occupant model. The lower limb-pelvis and lumbar spine regions of the human model were preliminarily validated against the post mortem human surrogate (PMHS) test data recorded in four-point lateral knee bending tests, pelvic impact tests, and lumbar spine bending tests. Then, pedestrian-to-vehicle impact simulations were performed using the whole pedestrian model and the results were compared to corresponding pedestrian PMHS tests. Overall, the preliminary simulation results showed that lower leg response is close to the upper boundaries of PMHS corridors. The pedestrian kinematics predicted by the model was also in the overall range of test data obtained with PMHS with various anthropometries. In addition, the model shows capability to predict the most common injuries observed in pedestrian accidents. Generally, the validated pedestrian model may be used by safety researchers in the design of front ends of new vehicles in order to increase pedestrian protection.


2019 ◽  
Vol 16 (03) ◽  
pp. 1842012 ◽  
Author(s):  
Zimo Zhu ◽  
Donna C. Jones ◽  
G. R. Liu ◽  
Sajjad Soleimani ◽  
Xu Huang ◽  
...  

Finite element (FE) analysis has been widely used to investigate bone responses to mechanical loading. Research in long bones has been straight forward because modeling of these bones requires only two material properties. Such an FE model may provide an adequate approximation of the anatomy for many cases. However, a more detailed model of skull bones is needed to accurately capture its complex structure of multiple bone pieces and the various mineral densities distributed throughout these bone pieces. Unfortunately, FE model development incorporating both complex geometries and anatomically accurate material properties is both computationally and labor intensive. In this study, a method is proposed to automatically segment micro-computed tomography ([Formula: see text]-CT) scan images of bone pieces to build an FE model of a full swine hemi-skull. Using the Digital Imaging and Communications in Medicine (DICOM) files from scanned bones, the complete geometry of each bone piece is recreated through seven customized processing algorithms. After assembling the bone pieces to form the skull, experimentally derived Young’s modulus values are correlated to grayscale values to produce a detailed FE model for accurate simulation. This detailed skull model can be used to predict strain/stress patterns in response to various loading regimes to facilitate research questions in fracture healing and growth, as well as bone tissue engineering and bone mineral density loss (e.g., osteoporosis).


Author(s):  
Li-Xin Guo ◽  
Ee-Chon Teo

To understand the dynamic characteristics of the human spine, a detailed three-dimensional finite element model of the lower thorax to pelvis segment, T12-pelvis, was developed based on actual vertebral geometry. After modal analysis, the resonant frequencies of different spinal segments were obtained. The vibration mode of T12-pelvis shows that the human upper body mainly performs the vertical motion during whole-body vibration and the lumbar spine segment conducts translation and rotation in the sagittal plane. The lower segments of the lumbar spine move in flexion and the upper lumbar segments move in extension. This investigation may be helpful in understanding further the biomechanical behaviour of the human spine under the condition of whole-body vibration and to offer potential references for spinal disease treatments and product design in industry.


2017 ◽  
Vol 140 (1) ◽  
Author(s):  
Costin D. Untaroiu ◽  
Wansoo Pak ◽  
Yunzhu Meng ◽  
Jeremy Schap ◽  
Bharath Koya ◽  
...  

Pedestrians represent one of the most vulnerable road users and comprise nearly 22% the road crash-related fatalities in the world. Therefore, protection of pedestrians in car-to-pedestrian collisions (CPC) has recently generated increased attention with regulations involving three subsystem tests. The development of a finite element (FE) pedestrian model could provide a complementary component that characterizes the whole-body response of vehicle–pedestrian interactions and assesses the pedestrian injuries. The main goal of this study was to develop and to validate a simplified full body FE model corresponding to a 50th male pedestrian in standing posture (M50-PS). The FE model mesh and defined material properties are based on a 50th percentile male occupant model. The lower limb-pelvis and lumbar spine regions of the human model were validated against the postmortem human surrogate (PMHS) test data recorded in four-point lateral knee bending tests, pelvic\abdomen\shoulder\thoracic impact tests, and lumbar spine bending tests. Then, a pedestrian-to-vehicle impact simulation was performed using the whole pedestrian model, and the results were compared to corresponding PMHS tests. Overall, the simulation results showed that lower leg response is mostly within the boundaries of PMHS corridors. In addition, the model shows the capability to predict the most common lower extremity injuries observed in pedestrian accidents. Generally, the validated pedestrian model may be used by safety researchers in the design of front ends of new vehicles in order to increase pedestrian protection.


Author(s):  
Ashwini Gautam ◽  
Chris Fuller ◽  
James Carneal

This work presents an extensive analysis of the properties of distributed vibration absorbers (DVAs) and their effectiveness in controlling the sound radiation from the base structure. The DVA acts as a distributed mass absorber consisting of a thin metal sheet covering a layer of acoustic foam (porous media) that behaves like a distributed spring-mass-damper system. To assess the effectiveness of these DVAs in controlling the vibration of the base structures (plate) a detailed finite elements model has been developed for the DVA and base plate structure. The foam was modeled as a poroelastic media using 8 node hexahedral elements. The structural (plate) domain was modeled using 16 degree of freedom plate elements. Each of the finite element models have been validated by comparing the numerical results with the available analytical and experimental results. These component models were combined to model the DVA. Preliminary experiments conducted on the DVAs have shown an excellent agreement between the results obtained from the numerical model of the DVA and from the experiments. The component models and the DVA model were then combined into a larger FE model comprised of a base plate with the DVA treatment on its surface. The results from the simulation of this numerical model have shown that there has been a significant reduction in the vibration levels of the base plate due to DVA treatment on it. It has been shown from this work that the inclusion of the DVAs on the base plate reduces their vibration response and therefore the radiated noise. Moreover, the detailed development of the finite element model for the foam has provided us with the capability to analyze the physics behind the behavior of the distributed vibration absorbers (DVAs) and to develop more optimized designs for the same.


2013 ◽  
Vol 456 ◽  
pp. 576-581 ◽  
Author(s):  
Li Fu Xu ◽  
Na Ta ◽  
Zhu Shi Rao ◽  
Jia Bin Tian

A 2-D finite element model of human cochlea is established in this paper. This model includes the structure of oval window, round window, basilar membrane and cochlear duct which is filled with fluid. The basilar membrane responses are calculated with sound input on the oval window membrane. In order to study the effects of helicotrema on basilar membrane response, three different helicotrema dimensions are set up in the FE model. A two-way fluid-structure interaction numerical method is used to compute the responses in the cochlea. The influence of the helicotrema is acquired and the frequency selectivity of the basilar membrane motion along the cochlear duct is predicted. These results agree with the experiments and indicate much better results are obtained with appropriate helicotrema size.


2015 ◽  
Vol 712 ◽  
pp. 63-68
Author(s):  
Przemysław Osocha ◽  
Bohdan Węglowski

In some coal-fired power plants, pipeline elements have worked for over 200 000 hours and increased number of failures is observed. The paper discuses thermal wear processes that take place in those elements and lead to rupture. Mathematical model based on creep test data, and describing creep processes for analyzed material, has been developed. Model has been verified for pipeline operating temperature, lower than tests temperature, basing on Larson-Miller relation. Prepared model has been used for thermal-strength calculations based on a finite element method. Processes taking place inside of element and leading to its failure has been described. Than, basing on prepared mathematical creep model and FE model introduced to Ansys program further researches are made. Analysis of dimensions and shape of pipe junction and its influence on operational element lifetime is presented. In the end multi variable dependence of temperature, steam pressure and element geometry is shown, allowing optimization of process parameters in function of required operational time or maximization of steam parameters. The article presents wide range of methods. The creep test data were recalculated for operational temperature using Larson-Miller parameter. The creep strain were modelled, used equations and their parameters are presented. Analysis of errors were conducted. Geometry of failing pipe junction was introduced to the Ansys program and the finite element analysis of creep process were conducted.


Author(s):  
Chen Xin ◽  
Qin Ye ◽  
Yuan Xiguang ◽  
Zhang Ping ◽  
Sun Jian

Abstract According to the real situation, a new method of updating the finite element model (FEM) of a combined structure step by step is proposed in this paper. It is assumed that there are two types of error when establishing the FEMs. One of them results from the simplifications, in fact, it is severe for complicated structures, which usually assume many simplifications; the other is from the process of identifying structural joint parameters. For this reason, it is recommended that the FEM should be established in two stages. At the first stage, the local physical parameters relating with the simplifications are corrected by using the dynamic test data of the corresponding substructures. Then, the structural joint parameters that link the substructures are corrected by the dynamic test data of the combined structure as a whole. The updating formula is presented and proved, and its algorithm is also described. And the experimental results show that the efficiency and accuracy of the proposed method are quite satisfactory.


Author(s):  
J. Rodriguez ◽  
M. Him

Abstract This paper presents a finite element mesh generation algorithm (PREPAT) designed to automatically discretize two-dimensional domains. The mesh generation algorithm is a mapping scheme which creates a uniform isoparametric FE model based on a pre-partitioned domain of the component. The proposed algorithm provides a faster and more accurate tool in the pre-processing phase of a Finite Element Analysis (FEA). A primary goal of the developed mesh generator is to create a finite element model requiring only essential input from the analyst. As a result, the generator code utilizes only a sketch, based on geometric primitives, and information relating to loading/boundary conditions. These conditions represents the constraints that are propagated throughout the model and the available finite elements are uniformly mapped in the resulting sub-domains. Relative advantages and limitations of the mesh generator are discussed. Examples are presented to illustrate the accuracy, efficiency and applicability of PREPAT.


2021 ◽  
Author(s):  
Zwelihle Ndlovu ◽  
Dawood Desai ◽  
Thanyani Pandelani ◽  
Harry Ngwangwa ◽  
Fulufhelo Nemavhola

This study assesses the modelling capabilities of four constitutive hyperplastic material models to fit the experimental data of the porcine sclera soft tissue. It further estimates the material parameters and discusses their applicability to a finite element model by examining the statistical dispersion measured through the standard deviation. Fifteen sclera tissues were harvested from porcine’ slaughtered at an abattoir and were subjected to equi-biaxial testing. The results show that all the four material models yielded very good correlations at correlations above 96 %. The polynomial (anisotropic) model gave the best correlation of 98 %. However, the estimated material parameters varied widely from one test to another such that there would be needed to normalise the test data to avoid long optimisation processes after applying the average material parameters to finite element models. However, for application of the estimated material parameters to finite element models, there would be needed to consider normalising the test data to reduce the search region for the optimisation algorithms. Although the polynomial (anisotropic) model yielded the best correlation, it was found that the Choi-Vito had the least variation in the estimated material parameters thereby making it an easier option for application of its material parameters to a finite element model and also requiring minimum effort in the optimisation procedure. For the porcine sclera tissue, it was found that the anisotropy more influenced by the fiber-related properties than the background material matrix related properties.


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